Refined Avian Risk Assessment for Chlorpyrifos in the United States - Reviews of Environmental Contamination and Toxicology - page 210

Granular CPY is registered for a wide variety of crops including brassica
vegetables, corn, onion, peanut, sugar beet, sunfl ower, and tobacco under the trade
name Lorsban 15G. Consumption of grit is required by many birds to aid in diges-
tion of hard dietary items such as seeds and insects. Because CPY granules are in
the same size range as natural grit particles consumed by birds, there is a potential
for birds to mistakenly ingest granular CPY instead of natural grit. We developed
the Granular Pesticide Avian Risk Model (GranPARAM) to simulate grit ingestion
behavior by birds. The model accounts for proportion of time that birds forage for
grit in treated fi elds, relative proportions of natural grit versus pesticide granules on
the surface of treated fi elds, rates of ingestion of grit, attractiveness of pesticide
granules relative to natural grit and so on. For CPY, each model simulation included
20 birds on each of 1,000 fi elds to capture variability in rates of ingestion of grit and
foraging behavior between birds within a focal species, and variability in soil com-
position between fi elds for the selected use pattern. The estimated dose for each bird
was compared with randomly chosen doses from relevant dose-response curves for
CPY. Our analysis for a wide variety of use patterns on the Lorsban 15G label found
that granular CPY poses little risk of causing mortality to bird species that frequent
treated fi elds immediately after application. The predictions of the model have been
confi rmed in several avian fi eld studies conducted with Lorsban 15G at application
rates similar to or exceeding maximum application rates on the Lorsban 15G label.
Acknowledgments The development of LiquidPARAM and this manuscript was guided by the
advice of two expert panels, one for carbofuran and the other for CPY. The authors wish to thank
the members of the expert panels that included Lou Best, Larry Brewer, Chris Cutler, Jeff Giddings,
Don Mackay, John Purdy, and Marty Williams. The authors also thank Don Carlson of FMC
Corporation, Dylan Fuge from Latham and Watkins LLP, and Nick Poletika and Mark Douglas
from Dow AgroSciences for their helpful contributions to the development and preparation of this
manuscript. We thank the anonymous reviewers of this paper for their suggestions and constructive
criticism. Prof. Giesy was supported by the Canada Research Chair program, a Visiting
Distinguished Professorship in the Department of Biology and Chemistry and State Key Laboratory
in Marine Pollution, City University of Hong Kong, the 2012 “High Level Foreign Experts”
(#GDW20123200120) program, funded by the State Administration of Foreign Experts Affairs,
the P.R. China to Nanjing University and the Einstein Professor Program of the Chinese Academy
of Sciences. This study was funded by Dow AgroSciences.
Open Access This article is distributed under the terms of the Creative Commons Attribution
Noncommercial License, which permits any noncommercial use, distribution, and reproduction in
any medium, provided the original author(s) and source are credited.
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